JPH074891B2 - Method for manufacturing easily openable sealed bag - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention does not impair the practical strength of a bag and does not inadvertently break the bag during transportation or handling.
The present invention relates to a method for manufacturing an easily openable sealed bag that can be easily opened with the force of fingers.

[Prior Art] Recently, a plastic film and a laminated film of a plastic and a metal such as aluminum foil or another material such as paper are lightweight and have excellent airtightness, high strength, and convenient for handling. No special adhesive is needed to seal the product, and it is sufficient to simply heat-seal it, so it can seal foods, chemicals, small items, etc., as well as liquids, powders, pastes, solids, and other products of various types and shapes. Used for bags.

These sealed bags pose the problem that the advantage of the material is resistance to tearing upon opening, which makes it difficult to tear.

On the other hand, the film for the above-mentioned sealed bag is tough, but on the other hand, once a scratch is generated, the scratch tends to propagate. Therefore, if one scratch is made on the edge portion in advance and the scratch is pulled as a break, It has the property of tearing easily with only the force of.

Therefore, a method of providing a cut (I notch) with a length of 2 mm or more in the transverse direction at the edge of the heat-sealed portion of the sealed bag is used. In this case, the edge of the bag is torn. There is a drawback that it is difficult to find out if the mouth is provided.

V-shaped scratches (V notches) may also be provided on the edge, and this method makes it easier to find the break, but when making and filling a large amount of bags, V-shaped cut pieces are used. Tends to scatter and adhere to packaging products, and the working environment tends to deteriorate. Further, USP 3,650,461 shows an example in which a round through hole is provided in the seal portion, but this also has the same problem as in the case of giving a round cut piece and giving the above V-shaped scratch. Further, when tearing with a finger, the stress concentrates around the round through hole, but there is a problem that a considerable force is required for tearing because elongation occurs around the round through hole.

In any case, since the breakage points of these methods are limited to a specific part, that part is not always the desired part, and the breakage propagates in an undesired direction, so that the contents are spread to the surroundings. There was inconvenience such as scattering. Also, the above I notch,
For V-notches, usually large notches (minimum length 2 mm)
Therefore, if the film before bag making is notched, it may be easily broken, and it may be impossible to make a bag.

Also, in Japanese Utility Model Publication No. 54-22484, tear initiation consisting of multiple pores (through holes with fracture fragments), embossed holes, or small cuts arranged inward from the edge and becoming smaller in sequence. Disclosed is a plastic film bag in which a series of dots is provided over at least one side of a seal portion. However, of the bags disclosed in Japanese Utility Model Publication No. 54-22484,
For those with pores and those with small cuts, once tearing starts, scratches will rapidly propagate along the row of tear start points, causing careless bag breakage during transport and handling, There is a problem that the contents easily leak. In addition, since the object provided with the embossed hole is not a through hole, a large force is required to start tearing, and there is a problem that it is difficult to propagate a scratch.

Further, Japanese Patent Laid-Open No. 58-160251 discloses a subdivided bag formed by fusing at least three sides, in which a large number of scratches are densely packed on the edge portion of the sheet forming the bag substantially at right angles to the edge line. A sealed subdivision bag is provided. However, since this bag uses a grindstone or the like to form scratches, there is a problem that jagged scratches tend to cause aesthetic damage, and the scratches are likely to be uneven and uneven in size, directionality, etc. There is a problem that it does not go or goes, and the direction of tearing is not constant.

In addition to the above problems, depending on the shape of the bag, only a part of the bag is opened, which is inconvenient in some cases. That is, for example, a so-called overlap in which a notch is provided and a vertical seal is provided at the central portion in the vertical direction as shown in FIG. 21 and FIG. In the case of the method, even if the notch 7 is unsealed, the breaking stops at the fusion-bonded portion and only half of the bag tends to open. In this case, there is the inconvenience of forcibly taking out the contents from the narrow opening, and it is more difficult to take out the contents, especially if the contents are hard rod-shaped, and the width of the contents is narrow when the contents are medical articles. Even though it is close to the width of the bag, it can only be opened halfway, which makes it extremely difficult to remove.

[Problems to be Solved by the Invention] The present invention has been made in view of the above points, and since a missing portion does not occur when a scratch is formed at a tear start point,
The method of manufacturing a hermetically sealed bag having no flaws in the product, reducing the practical strength of the bag, and having an ideal scar that can be opened from any part with the force of a finger is provided. This is a problem to be solved.

[Means and Actions for Solving the Problem] That is, according to the present invention, in a method for manufacturing a sealed bag by heat-sealing the film 8 constituting the bag at a position along the edge line 2 of the bag, A film 8 obtained by forming a large number of scratches 1 penetrating through the film to be the layer 16 at a position along the edge line 2 of the bag when the bag is formed, and then melt-laminating a heat-sealing layer 17 on one surface thereof. It is a method for manufacturing an easily-openable sealed bag, which is characterized in that the heat-sealing is performed along an edge line 2 of the bag along which the scratch 1 forming portion extends (see FIG. 1 or 2).

The base material layer 16 of the film 8 used in the present invention is a layer of a material that is not melted by heat during heat fusion, and is used for printing, laminating,
Any material can be used as long as it has strength that can withstand processing such as bag making and subsequent storage and distribution, and polyamide (nylon), polyester, biaxially oriented polypropylene, cellophane, hard vinyl chloride resin, etc. are used. Since these base material layers 16 are tough, it is naturally difficult to start breaking with the force of fingers.

In the present invention, another plastic material that can be heat-sealed to these base material layers 16, that is, a film obtained by laminating a heat-sealing layer 17 is used. The heat fusion layer 17 is a layer made of a material that is melted by heat during heat fusion, and as this material,
Low-density polyethylene (high-pressure method polyethylene, low-pressure method linear low-density polyethylene), olefin resin such as unstretched polypropylene, polyethylene-vinyl acetate copolymer,
An ethylene ionomer or the like is used. The heat fusion temperature varies depending on the pressing pressure, pressing time, film thickness, type, etc., but it is carried out at 80 to 180 ° C., usually 120 to 150 ° C., and at such a temperature, it becomes a molten state, at least a semi-molten state. Is preferred.

The heat-sealing layer 17 may be formed of the above heat-sealable material alone, or may be further provided with a layer of an anchor coating agent for increasing the adhesive strength. Many of the anchor coating agents are isocyanate-based ones which show excellent properties.

The heat fusion layer 17 preferably has a lower tensile strength than the base material layer 16. Further, the heat-sealing layer 17 preferably has a tear resistance larger than that of the base material layer 16. Here tear resistance is
It is measured by the method based on JIS P 8116 and refers to the tear resistance of a notched sample.

More specifically, the material of the base material layer 16 and the heat-sealing layer 17 is selected such that the material of the heat-sealing layer 17 is 2 / the tensile strength of the material of the base material layer 16.
3 or less and 1/20 or more tensile strength, and the material of the heat-sealing layer 17 has a tear resistance of the material of the base material layer 16 (JIS P 811
It is preferably 5 times or more and 150 times or less than 6). The measurement examples of commercially available plastic films are shown below.

The base material layer 16 and the heat fusion layer are selected from the materials having the above strength range.
Assuming that 17 is formed, the thickness ratio of the base material layer to the heat fusion layer is 5: 1.
~ 1: 10 is preferred. More preferably the base material layer 16 has a thickness of 10 to
50 μm, thickness of heat-sealing layer 17 is 10 to 100 μm, total thickness is 20 to 150
A thickness of μm is preferable because it provides a good balance between easy-open property and bag-breaking resistance. That is, tearing from the scratch 1 portion of the base material layer 16 is facilitated, and as will be described later, due to the presence of the heat-sealing layer material 18 in the scratch 1 portion, inadvertent and rapid propagation of the tear is suppressed. Prevents accidental bag breakage during transportation and handling.

It is preferable to use, as the base material layer 16, a film of a resin having both barrier properties, strength and heat resistance such as polyester resin and polyamide resin, or a laminated film containing at least one of these films, as a sealed bag applicable to high-level packaging. A laminate of an aluminum foil and a plastic layer or a film in which a metal thin film such as aluminum is formed on a plastic film by vapor deposition, sputtering, ion plating or the like is also preferable as the base material layer having a good barrier property. Further, for example, a laminated film in which a vinylidene chloride-based barrier layer is further laminated on a plastic layer of polyester, polyamide, polypropylene or the like is also preferable.

Further, for example, paper / PE ₁ / AC / PET / PE ₂ (where PET is a polyethylene terephthalate layer as the base material layer 16, AC is an anchor coat layer, and PE ₂ is a polyethylene layer as the heat-sealing layer 17). PE ₁ represents polyethylene as an adhesive.) Such as a paper layer laminated on the side opposite to the surface of the base material layer 16 on which the heat-sealing layer 17 is provided, or PET / PE ₁ / A laminated material such as paper / PE ₂ is preferable in terms of aesthetics because the scratches 1 are hidden by the paper or become inconspicuous.

The film 8 used in the present invention has a large number of scratches 1 formed therein, and the scratches 1 do not generate broken fragments such as punching and notches but generate broken fragments such as cuts. It refers to a scratch that is formed without.

A large number of the scratches 1 are formed as a group, and the formation position thereof is a position along the edge line 2 of the bag when the bag is formed. Here, forming the scar 1 at a position along the edge line 2 of the bag means not only the formation of the scratch 1 on the edge line 2 of the bag but also the formation of the scratch 1 slightly inward of the edge line 2 of the bag. It also means formation. The scar 1 is the film 8 used especially
If it is thick and tough, it must be provided on the edge line 2 of the bag, but if the film 8 to be used is thin, it is desirable to form it on the inside 0.5 to 3 mm of the edge line 2 of the bag. .

The scar 1 has an elongated shape in which the length is longer than the width, and the length thereof is 0.5 mm or less, preferably 0.3 mm or less, 0.1 mm or more, and is formed in the transverse direction with respect to the edge line 2 of the bag. . If such a scar 1 exists on the edge line 2 of the bag, when the portion is pulled with a finger, the scar 1 starts to tear from the inner tip 4 of the scar 1. When the scar 1 exists slightly inside the edge line 2 of the bag, when stress as shown by an arrow in FIG. 3 is applied, it is applied from the outer tip 3 of the scar 1 to the edge line 2 and the third
As shown by the broken line arrow in the figure, it starts to tear, and after the edge line 2 side tears, as shown in FIG. 4, it begins to tear in the transverse direction from the inner tip 4 of the scar 1.

Therefore, the scar 1 is ideally 90 ° with respect to the edge line 2, but within the range of 70 ° to 110 °, preferably 75 ° to 105 °.
Within the range, the object of the present invention is achieved.

The scratches 1 may be formed in one line or in two or more lines as long as they are formed along the edge line 2 of the bag when formed into a bag. When forming multiple rows of scars 1, the space between rows is 5 mm
It is preferably within 3.5 mm, and more preferably within 3.5 mm. The scratches 1 may be formed in a zigzag pattern as shown in FIG. 1 or may be linearly aligned as shown in FIG.

The scratches 1 may be formed as a series of groups extending over the entire length of the edge line 2 of the bag, but may be formed only in a part thereof or may be formed as groups arranged intermittently.

The scar 1 is formed by the following method.

That is, it is a method in which the scratches 1 penetrating the base material layer 16 are provided and then the heat-sealing layer 17 is melt-laminated on one surface thereof.
The position where the scar 1 is formed is the edge line 2 of the bag when formed into a bag.
It is a part along.

As described above, when the heat-sealing layer 17 is melt-laminated after the scratches 1 penetrating the base material layer 16 are provided, as shown in FIGS. 6 (a) and 6 (b), the base material layer 16 is formed. Part or all of the formed scar 1 is filled with the heat-sealing layer material 18 when the heat-sealing layer 17 is melt-laminated, and closes part or all of the scratch 1. That is, the scar 1 is blocked by the heat-sealing layer material 18 even before fusion for forming a bag.

The heat-sealing for forming the bag is carried out along the edge line 2 of the bag. Here, the heat fusion along the edge line 2 of the bag means not only the heat fusion on the edge line 2 of the bag but also the heat fusion slightly inside the edge line 2 of the bag. To do. Specifically, when the group of the formed scratches 1 is entirely included in the fusion-bonded portion, and when a part of the group of the scratches 1 is not included in the fusion-bonded portion on the outside of the fusion-bonded portion. In some cases, it may be left in the fused portion. In the case of the present invention, particularly in the latter case, the scar 1 at the non-fused portion is also blocked by the heat fusion layer material 18.

As shown in FIG. 5 (a), the state of the fusion-bonded portion includes a scratch 1 on one base layer 16 of the front and back films 8 and a scratch 1 on the other base layer 16 that are fused to each other. When the two base materials are displaced from each other, as shown in FIG. 5 (b).
There are cases where the scratches 1 of 16 and the scratches 1 of the other base material layer 16 are at positions where they overlap each other. When the tear strength of the base material layer 16 is extremely high, it is preferable to set the scratches 1 so as to overlap each other from the viewpoint of easy opening. When the scratches 1 on one of the base material layers 16 and the scratches 1 on the other base material layer 16 are positioned so as to overlap each other, the easy opening property is sufficiently exhibited even if the pitch of the scratches 1 is long, For example 5m
The pitch can be extended to about m. When the scratches 1 on one of the base material layers 16 and the scratches 1 on the other base material layer 16 are displaced from each other, the pitch of the scratches 1 is 1.5 mm or less, preferably 1.0 to 1.5 mm. It is preferable to adjust the degree to ease of opening.

As the form of the bag, there are a three-way seal type as shown in FIG. 1 (c) and FIG. 2 (c), a four-way seal type as shown in FIG. Reference numeral 5 is a vertical fusion portion, and 6 is a horizontal fusion portion. In the case of using an automatic bag-making filling machine of mass production type which simultaneously cuts the film 8 in the longitudinal direction and makes two or more bags, several groups of scratches 1 are provided in the longitudinal direction. Further, as shown in FIG. 8, when a film 8 having a group of scratches 1 in the form of a grid is provided in the vertical and horizontal directions, a four-sided seal type bag which can be broken from any of the four sides can be obtained.

Further, there is a three-way seal type bag as shown in FIG. First
FIG. 10 is an enlarged cross-sectional perspective view of FIG. 9, and 7 is an I notch. In this case, this is a so-called overlap-type fusing method in which the films 8 to be fused are brought close to each other in the opposite direction and overlapped, and the fusing part does not project from the bag surface. Since a group of scratches 1 is provided along the edge of the longitudinal fusion-bonded portion 5,
The tearing does not stop at the fusion-bonded portion 5 in the vertical direction, and cutting and opening can be performed over the entire width. Therefore, it is possible to easily take out a solid rod-like substance or a wide substance having a width close to the width of the bag.

The scar imparting tool for forming the group of scars 1 penetrating the base material layer 16 is not particularly limited, but a large number of elongated blade edges may be provided on the circumferential surface of the metal roll or the flat surface of the metal plate.

For example, as shown in FIG. 11, a quasi-triangular cut 21 is made in the smooth metal surface 20, and the bottom of the quasi-triangular shape is used as a central axis, and the metal portion cut away from the smooth metal surface 20 is cut. When standing up, the protrusion 10 protrudes and the cut part is dented.
Remains as 11. The surface of the protrusion 10 on the recessed side, that is, the angle formed by the flat standing surface 12 with respect to the smooth metal surface 20 is 60 to 100 °, preferably 80 to 100 °. Such protrusions 10 may be arranged in a line in one or more lines and the metal may be quenched and used.

FIG. 13 is a perspective view of a processing roll 13 provided with the above-mentioned protrusions 10 on the circumferential surface, and FIG. 14 is an enlarged plan view of a portion indicated by a chain line in FIG.

When a film to be the base material layer 16 (hereinafter referred to as “film 16”) is pressed by the protrusions 10 as shown in FIG.
One edge of the blade acts as a blade edge, and the side edge of the upright surface 12 side enters the film 16 straight. The film 16 on the side of the raised surface 19 is expanded by the raised surface 19, and as a result, a flat crescent-shaped scar 1 as shown in FIG. 15 (a) is formed. Further, as shown in FIG. 15 (b), the scar 1 is formed by straightening the portion where the upright surface 12 is pushed in and deforming the portion where the raised surface 19 is pushed in obliquely downward, resulting in different steps. Has distortion at the same time. That is, there is a portion that has a distortion and a portion that does not have a distortion. This strained portion has no difference during the subsequent melt lamination, and internal strain remains even when it returns to its original state, so that the internal strain reduces the strength and causes strain. It has the important effect that it can be easily torn with the fingers from the boundary between the part and the part that does not. Moreover, unlike the case of cutting with a normal blade, the scratches 1 are formed by being pushed, so that cracks are formed at both tips of the scratches 1 where stress concentrates, and such an unreasonable force is not applied. The part of is kept smooth. And, this crack gives a great cutting start effect at the time of cutting. The scar 1 having the shape shown in FIG. 15 formed by the scar imparting tool shown in FIG. 11 has substantially the same shape as that shown in FIGS. 5 and 6 when the melt lamination is performed. Return to the flat state.

FIG. 16 shows a film 16 using the processing roll 13 shown in FIG.
It is explanatory drawing which shows one example which processes.

The processing roll 13 and the pressing roll 14 are rotating in the opposite directions at the same peripheral speed while being in contact with each other. The film 16 passes through the contact portion between the rolls 13 and 14. At this time, the film 16 is pressed by the projections 10 of the processing roll 13, and the scratches 1 penetrating through the film 16 are arranged as shown in FIG. Reference numeral 15 is a raw material for unwinding the film 16.

In addition, as a scar imparting tool for imparting the penetrating scar 1,
A flat bar provided with protrusions 10 as shown in FIG. 19 or a plate-like body cut out from a disc provided with protrusions 10 as shown in FIG. 20 can be used.

The present flaw imparting tool is preferably made of a hard material, and in addition to quenched steel, ceramics such as silicon carbide, titanium carbide and silicon nitride can also be used. Further, those obtained by finishing the tool shape with a metal material and then coating it with a thin film of silicon carbide, titanium carbide or the like by a CVD method, a PVD method or the like are also preferable because they have excellent wear resistance and do not deteriorate the sharpness.

[Example] Example 1 A total thickness of 70 μm having the following layer constitution by an extrusion laminating method.
A composite laminate film having a width of 770 mm and a width of 770 mm was produced. However, the isocyanate anchor coating agent was coated on a biaxially stretched 6-nylon film by a gravure coating method, and the low density polyethylene layer and the ethylene-vinyl acetate copolymer resin layer were laminated by a tandem extrusion laminating method.

ON _{# 15} / AC / PE ₂₅ / EVA ₃₀ ON _{# 15} : Biaxially stretched 6-nylon film (Emblem manufactured by Unitika Ltd.) Thickness: 15 μm AC: Imine-based anchor coating agent (EL manufactured by Toyo Morton Co., Ltd. -200 and CAT-200 mixed at 13: 1) ...... Solid content 0.02g / m ² PE ₂₅ : Low density polyethylene (Asahi Kasei Kogyo Co., Ltd., Suntech LD, L-1850A) ...... 25μm EVA ₃₀ : Ethylene-vinyl acetate copolymer resin (Asahi Kasei Kogyo Co., Ltd., Suntech EVA, EL-0990) ...... Thickness 30 μm Scar 1 pierced through biaxially stretched 6-nylon film immediately before lamination in extrusion lamination process A group of
The tool shown in FIG. 13 was used as the scratch imparting tool. As the processing roll 13, leaving a smooth surface with a width of 1.5 mm in the center, the projections 10 with a maximum width of 0.5 mm shown in FIG.
A center-to-center distance of 0.5 mm was used, which was arranged in two rows (4 rows in total) in a zigzag pattern as shown in FIG. Biaxially stretched 6-Nylon film 10mm from both ends and width
A group of scratches 1 penetrating every 250 mm was processed into a linear shape.

The group of scratches 1 was processed as described above, and after the extrusion lamination, the central portion of the group of scratches 1 was cut. Therefore, the obtained film 8 had a width of 250 mm, and the groups of the scratches 1 were arranged at the sites separated by 0.75 mm or more from the edge lines on both sides. Here, the layer of ethylene-vinyl acetate copolymer is a heat-sealing layer.

Using the obtained film 8, 250 g of raw konjac was filled in an automatic bag-making filling machine into a pillow-type bag having its end edges fused.

There was no trouble in the strength of the film during the manufacturing process, transportation and storage, and it was possible to open the film by hand from any part of the vertical fusion-bonded part during use.

[Effects of the Invention] The present invention is as described above and has the following effects.

(A) The base material layer 16 is in a state of being easily torn due to the scratch 1. However, since the heat-sealing layer material 18 enters into the scratch 1 and closes it, the base material layer 16 is easily formed. Tear is prevented. Therefore, even if some tension is applied to the film 8 in the process until it is formed into a bag, the film 8 is not torn carelessly, and the handleability and workability are good.

(B) Even if the heat fusion performed along the edge line of the bag to form the bag deviates to the outside slightly above the portion where the scar 1 is formed, the scar 1 is closed before the heat fusion. Therefore, there are no penetrating scratches that would expose the inside of the bag to the outside air.

(C) The scar 1 is surely closed, and there is no possibility of omission of the wound, and the above-mentioned effect can be surely obtained.

(D) The resulting easily-openable sealed bag can be easily opened by the force of fingers, but for the reason shown in (a), the practical strength is not impaired, and the bag is not prepared during transportation or handling. It never breaks.

[Brief description of drawings]

FIGS. 1 (a) to (c) are explanatory views of the first invention, FIGS. 2 (a) to (c) are explanatory views of the present invention, and FIGS. 3 and 4 show a breaking action by a scratch. Explanatory views, FIGS. 5 (a) and 5 (b) are cross-sectional views showing the positional relationship of the scratches after heat fusion, and FIGS. 6 (a) and 6 (b) show the condition of the scratches after melt lamination according to the present invention. Sectional views shown in FIGS. 7, 7 and 9 are plan views showing an example of the obtained bag, FIG. 8 is an explanatory view of an example of giving a scar suitable for obtaining a four-side seal type bag, and FIG. FIG. 11 is an enlarged cross-sectional perspective view of the drawing, FIG. 11 is an enlarged view of the projection of the scratch imparting tool, and FIG. 12 is a cross-sectional view showing an example of a process of manufacturing the projection.
13 is a perspective view of the processing roll, FIG. 14 is an enlarged plan view of the circumferential surface of FIG. 13, and FIGS. 15 (a) and 15 (b) are explanatory views of the scratches formed by the protrusions of FIG. 11, respectively. , FIG. 16 is an explanatory view showing an example of film processing, FIG. 17 is a perspective view showing a process of manufacturing another scarring tool, FIG. 18 is a perspective view of a projection formed by the method of FIG. 17, FIG. 19 is a perspective view showing a scratch imparting tool in which a protrusion is provided on a flat bar, FIG. 20 is a perspective view showing a scar imparting tool in which a protrusion is provided on a plate-like body cut from a disc, and FIG. 21 is a conventional view. A perspective view showing an example of a sealed bag of
22 is an enlarged cross-sectional perspective view of the sealing bag of FIG. 1 ... scratch, 2 ... edge line, 3 ... outer tip, 4 ... inner tip,
5 ... longitudinal fusion portion, 6 ... lateral fusion portion, 7 ... I notch,
8 ... Film, 10 ... Protrusion, 11 ... Dimple, 12 ... Standing surface, 13 ...
Processing roll, 14 ... Press roll, 15 ... Original fabric, 16 ... Base material layer,
17 ... Heat-sealing layer, 18 ... Heat-sealing layer material, 19 ... Raised surface, 20 ... Metal smooth surface, 21 ... Notch, 22 ... Ridge line, 23 ... Cutlery.

Claims (1)

[Claims] 1. A method for producing a hermetically sealed bag by heat-sealing a film constituting a bag at a position along an edge line of the bag, wherein the bag serving as a base material layer is a bag. After forming a large number of scars penetrating in a location along the edge line of, using a film obtained by melt-laminating a heat-sealing layer on one surface thereof,
A method for producing an easily-openable sealed bag, characterized in that the heat fusion is performed along an edge line of the bag along which the scratch formation portion extends.